研究目的

Investigating the electronic structures and dynamics of photogenerated carriers in two-dimensional Janus transition metal dichalcogenides and graphene van der Waals sandwich heterojunction photovoltaic cells to enhance the separation and transfer of photogenerated carriers.

研究成果

The photogenerated carriers can transfer from monolayer JTMDs to the graphene layers with a preferred diffusion direction, facilitated by the intrinsic built-in electric field in JTMDs. The transfer process occurs within hundreds of femtoseconds and is motivated by nonadiabatic and adiabatic molecular dynamics mechanisms. However, the transfer of photogenerated holes (electrons) is prohibited in certain heterostructures due to large energy separation between donor and acceptor states. Stacking MoSSe and MoSeTe vertically can modulate the separation between donor and acceptor states to promote simultaneous transfer of photogenerated electrons and holes.

研究不足

The study is limited by the computational methods used, which may not fully capture all physical phenomena. The spin-orbit coupling (SOC) was not taken into consideration, and the PBE functional underestimates the bandgap, which could affect the accuracy of the results.